Apple released the first update to iOS 5 on Thursday, fixing a critical security hole and promising better battery life for iPhone 4S users. However, it now looks like Apple may have not sufficiently tested it before release. Users have begun reporting that the update not only fails to address battery life problems, but may in fact introduce a number of new issues.

The update was Apple's first public over-the-air "delta" update, downloading directly to a device over WiFi instead of requiring a full iOS download and update via iTunes. Several Ars readers reported the update downloading and installing without a hitch. Numerous other users, however, have chimed in on Apple's support forums to say they have noticed no improvement in battery life on the iPhone 4S after applying the update.

Furthermore, users are also reporting a rash of new problems that were apparently introduced by the 5.0.1 update. The Next Web reported that some users aren't getting a proper contact name displayed when receiving a call, despite the name and number appearing in a user's contact list. Meanwhile, GigaOm reported that users are complaining of microphone problems, WiFi signal issues, and difficulty connecting to cell networks.

These new issues so far appear to be scattered and inconsistent, so it's unclear what the causes might be. Thankfully—knock on wood—we haven't experienced any of these issues here in the Orbiting HQ just yet, but the day is still young. Have you applied the 5.0.1 update? Has it helped your battery life? Did it cause any new problems for you? Let us know in the comments.

Update: Apple has once again given a statement to All Things D about continuing battery life issues: "The recent iOS software update addressed many of the battery issues that some customers experienced on their iOS 5 devices. We continue to investigate a few remaining issues."